The present invention relates to pharmaceutical compositions which have a healing or anticomplementary action and which comprise at least one dextran derivative.
Different dextrans which are substituted by side chains carrying carboxylate and sulfonate groups have been described. In particular, dextran derivatives comprising, respectively, 83% or 110% of units substituted by carboxymethyl groups, 23% or 2.6% of units substituted by carboxymethylbenzylamide groups, and 13% or 36.5% of units substituted by sulfonate groups (sulfonate groups carried by the carboxymethylbenzylamide units), namely RGTA9 and RGTA11, respectively, have been described for their action, in vivo in rats, on skin repair (A. Meddahi et al., Path. Res. Pract., 1994, 190, 923-928; A Meddahi et al., Diabetes & Metabolism (Paris), 1996, 22, 274-278) and on muscle regeneration (A. Aamiri et al., Neuroscience Letters, 1995, 201, 243-246; J. Gautron et al., C. R. Acad. Sci. Paris, Life sciences, Cell biology, 1995, 318, 671-6; A. Aamiri et al., C. R. Acad. Sci. Paris, Life sciences, Neurosciences, 1995, 318, 1037-43).
As far as skin repair is concerned, A. Meddahi et al. (ibid) propose making good skin wounds using collagen pieces which have been soaked with a solution of RGTA9 or RGTA11; an improvement in the speed and the quality of skin regeneration is observed under these conditions. This improvement could be explained on the basis that the RGTA9 or RGTA11 trap, protect and release the endogenous growth factors which are naturally secreted during skin healing. Protection of the growth factors would make it possible to avoid their being degraded by the natural proteases, thereby preserving their ability to stimulate tissue repair.
In the field of muscle regeneration, A. Aamiri et al. and J. Gautron et al. (ibid) propose injecting rats, whose rapid muscles (EDL: Extensor Digitorium Longus) and/or slow muscles (soleus) have been crushed, with a solution of RGTA11. They observe an improvement in the regeneration of the muscles following this injection: the treated muscles exhibit a larger number of muscle fibers and more rapid reinnervation.
However, because of the method by which they are prepared, the abovementioned RGTA9 and 11 suffer from the drawback of exhibiting an irregular distribution of chemical (carboxymethyl, carboxymethylbenzylamide and sulfonate) groups and polysaccharide chains, leading to a heterogeneous final product whose properties are difficult to control.
The aim of the inventors has therefore been to select dextran derivatives which differ from the already-described compounds RGTA9 and 11 in order to provide for pharmaceutical compositions which have an anticomplementary or healing action, in particular in the fields of skin, muscle, ocular or gastric mucosal healing, which more satisfactorily meet practical requirements, in particular by exhibiting an increased activity, and which are suitable for administration to humans, this being in forms and at doses which are adjusted for optimum efficacy.